linux/drivers/watchdog/w83697ug_wdt.c
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   1/*
   2 *      w83697ug/uf WDT driver
   3 *
   4 *      (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
   5 *              reused original code to supoprt w83697ug/uf.
   6 *
   7 *      Based on w83627hf_wdt.c which is based on advantechwdt.c
   8 *      which is based on wdt.c.
   9 *      Original copyright messages:
  10 *
  11 *      (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
  12 *              added support for W83627THF.
  13 *
  14 *      (c) Copyright 2003 P\xC3\xA1draig Brady <P@draigBrady.com>
  15 *
  16 *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  17 *
  18 *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  19 *                              http://www.redhat.com
  20 *
  21 *      This program is free software; you can redistribute it and/or
  22 *      modify it under the terms of the GNU General Public License
  23 *      as published by the Free Software Foundation; either version
  24 *      2 of the License, or (at your option) any later version.
  25 *
  26 *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  27 *      warranty for any of this software. This material is provided
  28 *      "AS-IS" and at no charge.
  29 *
  30 *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  31 */
  32
  33#include <linux/module.h>
  34#include <linux/moduleparam.h>
  35#include <linux/types.h>
  36#include <linux/miscdevice.h>
  37#include <linux/watchdog.h>
  38#include <linux/fs.h>
  39#include <linux/ioport.h>
  40#include <linux/notifier.h>
  41#include <linux/reboot.h>
  42#include <linux/init.h>
  43#include <linux/spinlock.h>
  44#include <linux/io.h>
  45#include <linux/uaccess.h>
  46
  47#include <asm/system.h>
  48
  49#define WATCHDOG_NAME "w83697ug/uf WDT"
  50#define PFX WATCHDOG_NAME ": "
  51#define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  52
  53static unsigned long wdt_is_open;
  54static char expect_close;
  55static DEFINE_SPINLOCK(io_lock);
  56
  57static int wdt_io = 0x2e;
  58module_param(wdt_io, int, 0);
  59MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
  60
  61static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  62module_param(timeout, int, 0);
  63MODULE_PARM_DESC(timeout,
  64        "Watchdog timeout in seconds. 1<= timeout <=255 (default="
  65                                __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  66
  67static int nowayout = WATCHDOG_NOWAYOUT;
  68module_param(nowayout, int, 0);
  69MODULE_PARM_DESC(nowayout,
  70        "Watchdog cannot be stopped once started (default="
  71                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  72
  73/*
  74 *      Kernel methods.
  75 */
  76
  77#define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  78#define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
  79                                                        (same as EFER) */
  80#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  81
  82static void w83697ug_select_wd_register(void)
  83{
  84        unsigned char c;
  85        unsigned char version;
  86
  87        outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  88        outb_p(0x87, WDT_EFER); /* Again according to manual */
  89
  90        outb(0x20, WDT_EFER);   /* check chip version   */
  91        version = inb(WDT_EFDR);
  92
  93        if (version == 0x68) {  /* W83697UG             */
  94                printk(KERN_INFO PFX "Watchdog chip version 0x%02x = "
  95                        "W83697UG/UF found at 0x%04x\n", version, wdt_io);
  96
  97                outb_p(0x2b, WDT_EFER);
  98                c = inb_p(WDT_EFDR);    /* select WDT0 */
  99                c &= ~0x04;
 100                outb_p(0x2b, WDT_EFER);
 101                outb_p(c, WDT_EFDR);    /* set pin118 to WDT0 */
 102
 103        } else {
 104                printk(KERN_ERR PFX "No W83697UG/UF could be found\n");
 105                return;
 106        }
 107
 108        outb_p(0x07, WDT_EFER); /* point to logical device number reg */
 109        outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
 110        outb_p(0x30, WDT_EFER); /* select CR30 */
 111        c = inb_p(WDT_EFDR);
 112        outb_p(c || 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
 113}
 114
 115static void w83697ug_unselect_wd_register(void)
 116{
 117        outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
 118}
 119
 120static void w83697ug_init(void)
 121{
 122        unsigned char t;
 123
 124        w83697ug_select_wd_register();
 125
 126        outb_p(0xF6, WDT_EFER); /* Select CRF6 */
 127        t = inb_p(WDT_EFDR);    /* read CRF6 */
 128        if (t != 0) {
 129                printk(KERN_INFO PFX "Watchdog already running."
 130                        " Resetting timeout to %d sec\n", timeout);
 131                outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 132        }
 133        outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 134        t = inb_p(WDT_EFDR);    /* read CRF5 */
 135        t &= ~0x0C;             /* set second mode &
 136                                        disable keyboard turning off watchdog */
 137        outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 138
 139        w83697ug_unselect_wd_register();
 140}
 141
 142static void wdt_ctrl(int timeout)
 143{
 144        spin_lock(&io_lock);
 145
 146        w83697ug_select_wd_register();
 147
 148        outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
 149        outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
 150
 151        w83697ug_unselect_wd_register();
 152
 153        spin_unlock(&io_lock);
 154}
 155
 156static int wdt_ping(void)
 157{
 158        wdt_ctrl(timeout);
 159        return 0;
 160}
 161
 162static int wdt_disable(void)
 163{
 164        wdt_ctrl(0);
 165        return 0;
 166}
 167
 168static int wdt_set_heartbeat(int t)
 169{
 170        if (t < 1 || t > 255)
 171                return -EINVAL;
 172
 173        timeout = t;
 174        return 0;
 175}
 176
 177static ssize_t wdt_write(struct file *file, const char __user *buf,
 178                                                size_t count, loff_t *ppos)
 179{
 180        if (count) {
 181                if (!nowayout) {
 182                        size_t i;
 183
 184                        expect_close = 0;
 185
 186                        for (i = 0; i != count; i++) {
 187                                char c;
 188                                if (get_user(c, buf + i))
 189                                        return -EFAULT;
 190                                if (c == 'V')
 191                                        expect_close = 42;
 192                        }
 193                }
 194                wdt_ping();
 195        }
 196        return count;
 197}
 198
 199static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 200{
 201        void __user *argp = (void __user *)arg;
 202        int __user *p = argp;
 203        int new_timeout;
 204        static const struct watchdog_info ident = {
 205                .options =              WDIOF_KEEPALIVEPING |
 206                                        WDIOF_SETTIMEOUT |
 207                                        WDIOF_MAGICCLOSE,
 208                .firmware_version =     1,
 209                .identity =             "W83697UG WDT",
 210        };
 211
 212        switch (cmd) {
 213        case WDIOC_GETSUPPORT:
 214                if (copy_to_user(argp, &ident, sizeof(ident)))
 215                        return -EFAULT;
 216                break;
 217
 218        case WDIOC_GETSTATUS:
 219        case WDIOC_GETBOOTSTATUS:
 220                return put_user(0, p);
 221
 222        case WDIOC_SETOPTIONS:
 223        {
 224                int options, retval = -EINVAL;
 225
 226                if (get_user(options, p))
 227                        return -EFAULT;
 228
 229                if (options & WDIOS_DISABLECARD) {
 230                        wdt_disable();
 231                        retval = 0;
 232                }
 233
 234                if (options & WDIOS_ENABLECARD) {
 235                        wdt_ping();
 236                        retval = 0;
 237                }
 238
 239                return retval;
 240        }
 241
 242        case WDIOC_KEEPALIVE:
 243                wdt_ping();
 244                break;
 245
 246        case WDIOC_SETTIMEOUT:
 247                if (get_user(new_timeout, p))
 248                        return -EFAULT;
 249                if (wdt_set_heartbeat(new_timeout))
 250                        return -EINVAL;
 251                wdt_ping();
 252                /* Fall */
 253
 254        case WDIOC_GETTIMEOUT:
 255                return put_user(timeout, p);
 256
 257        default:
 258                return -ENOTTY;
 259        }
 260        return 0;
 261}
 262
 263static int wdt_open(struct inode *inode, struct file *file)
 264{
 265        if (test_and_set_bit(0, &wdt_is_open))
 266                return -EBUSY;
 267        /*
 268         *      Activate
 269         */
 270
 271        wdt_ping();
 272        return nonseekable_open(inode, file);
 273}
 274
 275static int wdt_close(struct inode *inode, struct file *file)
 276{
 277        if (expect_close == 42)
 278                wdt_disable();
 279        else {
 280                printk(KERN_CRIT PFX
 281                        "Unexpected close, not stopping watchdog!\n");
 282                wdt_ping();
 283        }
 284        expect_close = 0;
 285        clear_bit(0, &wdt_is_open);
 286        return 0;
 287}
 288
 289/*
 290 *      Notifier for system down
 291 */
 292
 293static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 294        void *unused)
 295{
 296        if (code == SYS_DOWN || code == SYS_HALT)
 297                wdt_disable();  /* Turn the WDT off */
 298
 299        return NOTIFY_DONE;
 300}
 301
 302/*
 303 *      Kernel Interfaces
 304 */
 305
 306static const struct file_operations wdt_fops = {
 307        .owner          = THIS_MODULE,
 308        .llseek         = no_llseek,
 309        .write          = wdt_write,
 310        .unlocked_ioctl = wdt_ioctl,
 311        .open           = wdt_open,
 312        .release        = wdt_close,
 313};
 314
 315static struct miscdevice wdt_miscdev = {
 316        .minor = WATCHDOG_MINOR,
 317        .name = "watchdog",
 318        .fops = &wdt_fops,
 319};
 320
 321/*
 322 *      The WDT needs to learn about soft shutdowns in order to
 323 *      turn the timebomb registers off.
 324 */
 325
 326static struct notifier_block wdt_notifier = {
 327        .notifier_call = wdt_notify_sys,
 328};
 329
 330static int __init wdt_init(void)
 331{
 332        int ret;
 333
 334        printk(KERN_INFO "WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising.\n");
 335
 336        if (wdt_set_heartbeat(timeout)) {
 337                wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 338                printk(KERN_INFO PFX
 339                        "timeout value must be 1<=timeout<=255, using %d\n",
 340                        WATCHDOG_TIMEOUT);
 341        }
 342
 343        if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 344                printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 345                        wdt_io);
 346                ret = -EIO;
 347                goto out;
 348        }
 349
 350        w83697ug_init();
 351
 352        ret = register_reboot_notifier(&wdt_notifier);
 353        if (ret != 0) {
 354                printk(KERN_ERR PFX
 355                        "cannot register reboot notifier (err=%d)\n", ret);
 356                goto unreg_regions;
 357        }
 358
 359        ret = misc_register(&wdt_miscdev);
 360        if (ret != 0) {
 361                printk(KERN_ERR PFX
 362                        "cannot register miscdev on minor=%d (err=%d)\n",
 363                        WATCHDOG_MINOR, ret);
 364                goto unreg_reboot;
 365        }
 366
 367        printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 368                timeout, nowayout);
 369
 370out:
 371        return ret;
 372unreg_reboot:
 373        unregister_reboot_notifier(&wdt_notifier);
 374unreg_regions:
 375        release_region(wdt_io, 1);
 376        goto out;
 377}
 378
 379static void __exit wdt_exit(void)
 380{
 381        misc_deregister(&wdt_miscdev);
 382        unregister_reboot_notifier(&wdt_notifier);
 383        release_region(wdt_io, 1);
 384}
 385
 386module_init(wdt_init);
 387module_exit(wdt_exit);
 388
 389MODULE_LICENSE("GPL");
 390MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
 391MODULE_DESCRIPTION("w83697ug/uf WDT driver");
 392MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 393